Split mandrel.



L. G. LARSEN.'

SPLIT MANDREL. APPLICATION FILED MAR. l0."l9l6.

1,265,793. Patented May 14, 1918.

ED STATES PATEN OFFICE.

LOUIS G LARSEN, OI BBIDGEPOBT, CONNECTICUT, ASSIGNOB TO AMERICAN GRAPHO-.PHONE COMPANY, OF BBIDGEPOBT, GONNECTIGUT, A CORPORATION OF WESTVIRGINIA.

SPLIT MANDREL.

Patented May 14, 1918.

Application filed March 10, 1916. Serial No. 83,828.

To all whom it may concern:

Be it known that I, LOUIS G. LARsnN, a citizen of Demnark, and a,resident of Bridgeport, Conn, have invented a new and useful Improvementin Split Mandrels, which invention i fully set forth in the followingspecification.

This invention relates to talking machines, and more particularly to asupport for the sound-record tablets thereof. It is customary withmachines employing the so-called cylindrical type of record tablettoprovide a mandrel having a slightly tapered exterior surface, the boreof the tablet being correspondingly tapered to fit the mandrel with sucha grip that it may be rotated thereby.

In the course of manufacture slight variations occur in the dimensionsof the surface of the mandrel and of the bore of the tablet, with theresult that diiferent tablets do not fit different mandrels with thesame degree of accuracy, both as, respects their relative taper and asrespects their mean dimensions. Furthermore, as the mandrel is-usuallymade of metal, its coeflicient of expansion and contraction is differentfrom that of the material of which the tablet is composed. Accordingly,chan es of temperature effect difi'erent degrees 0% expansioneandcontraction ofthe'tablet and mandrel. It is of importance, particularlywith machines that arising in the course of manufacture, as

above indicated, and owing to diiferent'temperature conditions, a tabletfrequently cannot be properly positioned upon a mandrel without dan erof breaking it. J

' It is an o ject of this invention to provide a mandrel whereby thetablet may be properly gripped for rotation, and whereby .it ma alwaysbe properly positloned, without anger of breakage from temperaturechanges or from undue pressure in attemptin to force the tablet to itsproper position. further ob'ect of this invention is to provide a manrel which shall resiliently grip the tablet only adjacent its ends,permitting ready application of the tablet upon and withdrawal of thesame from ,the mandrel. A still further object is to provide a mandrelsimple in construction, durable and trating a modified embodiment.

easy of manufacture.

It has heretofore been proposed to accommodate the varying dimensionsand temperature changes of mandrels and tablets by providing collapsiblemandrels. Structures of this type as provided have had the elements ofthe mandrel surface so mounted as to move toward and away from the axisof the mandrel, without change of angular relation of the elements tothe axis, or they have had a provision whereby the elements of themandrel surface are mounted at a fixed distance from the axis at one endand are collapsible to various extents at the opposite end. Suchstructures have the obection that, while providing in the formerinstance for temperature changes and variations of mean diameter arisingin manufacture, they have not provided for variations of taper in thebore of the tablet; or, providing in the latter instance for variationsof taper in the bore of the tablet, they have inadequately provided forvariations in its mean dimensions or temperature changes, whereby thetablet was improperly gripped at one end.

This invention comprises a mandrel provided with a rigid central portionand relatively and independently collapsible resilient end portions.While the resiliency of the end portions may be provided in a variety ofways, the'embodiments of the innin longitudinally of the mandrel andcon-' veniently produced by a series of saw-kerfs extending from eachend of the mandrel. To provide for resiliently gripping the tablet onlyat its ends, the central .portion of the mandrel is reduced in exteriordiameter.

As a mea-ns of illustrating this invention, two embodiments have beenselected, but it i to be understood that they are illustrative only,reference being had to the appended claims for a definition of thelimits of the invention. Referring to the accompanying drawings, onwhich similar characters of reference indicate corresponding parts inthe several figures,

Figure 1 is a perspective view of a mandrel embodyin the invention; Fig.2 is a ongitudinalcentral sectional view of the same, showing a record.tablet in position;

Fig. 3 is a fragment of a mandrel illushaving resilient end portions anda rigid intermediate portion, said end portions being provided withmeans adjacent the ends thereof whereby the tablet is supported out ofcontact with the central portion of said mandrel.

9. A mandrel for sound-record tablets having independently contractibleand expansible end portions, said portions being provided with meanswhereby the tablet is supported by .said end'portions only.

10. In combination with a sound-record tablet, a mandrel havingresilient end portions contacting with-said tablet only adjacent theends of said resilient portions.

11. A mandrel for sound-records comprising a rigid intermediate portion,a plurality of tongues at each end thereof, and means adjacent each endof said mandrel normally tending to relatively expand said tongues.

12. A mandrel for sound-record tablets comprising a rigidintermediateportion, a plurality of tongues at each end thereof, and aspring ring at each end of said mandrel normally tending to relativelyexpand said tongues.

13. A mandrel for sound-record tablets comprising a rigid intermediateportion, a plurality of tongues at each end thereof, a spring ring ateach end of said mandrel normally tending to relatively expand saidtongues, and means formed in said mandrel for maintaining said rings inposition.

14. In combination with a sound-record tablet, a mandrel provided withmeans to predeterminately position said tablet with respectthereto, saidmandrel having arigid" intermediate portion and its endsslotted toprovide a-plurality of spring tongues.

15. In combination with a sound-record, tablet, a mandrel provided withmeans to, predeterminately position said tablet with respect thereto,said mandrel comprising independently contractible and expansible endportions.

16. In combination with a sound-record tablet, a mandrel provided withmeans to predeterminately position said tablet with respect thereto,said mandrel comprising independently contractible and expansible endportions, and means on said end portions whereby said tablet issupported only adjacent its ends.

17 A mandrel for sound-record tablets comprising a rigid intermediateportion and resilient end portions provided with elevations adjacent theouter ends thereof.

18. A mandrel for sound-record tablets comprising independentlycontractible and expansible end portions provided with ele vationsadjacent the outer ends thereof.

19. A mandrel for sound-record tablets comprising a rigid intermediateportion, a plurality of tongues at each end thereof, means adjacent eachend of said mandrel normally tending to relatively expand said tongues,and means carried by said tongues for supporting the tablet out ofcontact with the central portion of said mandrel.

20. In combination with a sound-record tablet, a mandrel provided withmeans to predeterminately position said tablet with respect thereto,said mandrel comprising a rigid intermediate portion and a plurality ofspring tongues at each end thereof, said tongues having means wherebysaid tablet is supported out of contact with the central portion of saidmandrel.

21. A mandrel for sound-record tablets having a rigid intermediateportion and resilient endportions comprising a plurality ofspringtong'ues.

In testimony wher of I have signed this specification..--,

